One example of this kind of conventional transmission is disclosed in, for example, Japanese Unexamined Utility Model Publication No. 98953/1989. In this transmission, drive power is transmitted from an engine (not shown) to an input shaft 102 via a belt pulley 101 as shown in FIGS. 6 and 7. The input shaft 102 is supported by two superimposed bearings 104 and 105 in the upper portion of the casing 103. A small gear 106 attached at the lower end of the input shaft 102 meshes with a large gear 107. The ends of a supporting shaft 108 supporting the large gear 107 are fitted in and supported by a pair of recesses 103a, 103a that are formed in the casing 103. Drive power is transmitted from the supporting shaft 108 to an output shaft 111 via a speed change gear mechanism 109 and a clutch 110 after the rotational speed having been changed.
However, the above prior art transmission is too bulky with the two bearings being superimposed to stably support the input shaft. Therefore, the belt pulley, which is attached at the end of the input shaft to transmit drive power from the engine, is located distant from the ground. Thus, the prior art transmission could not address the need for a compact walking lawn mower.
In order to solve the above problem, it is an object of the present invention to provide a transmission wherein the distance between the belt pulley and the ground is reduced by reducing the height dimension of the transmission, thereby making a lawn mower compact.